Details About Overdose or Poisoning Generic Salt :: Propranolol
Drug Pharmacology ::
I. Pharmacology. Propranololis a nonselective beta-adrenergic blocker that acts on beta-1 receptorsin the myocardium and beta-2 receptors in the lung, vascular smoothmuscle, and kidney. Within the myocardium, propranolol depresses heartrate, conduction velocity, myocardial contractility, and automaticity.Although propranolol is effective orally, for toxicologic emergenciesit usually is administered by the intravenous route. After intravenousinjection, the onset of action is nearly immediate and the duration ofeffect is 10 minutes to 2 hours, depending on the cumulative dose. Thedrug is eliminated by hepatic metabolism, with a half-life of about 2–3hours. Propranolol also has antagonistic properties at the 5-HT1A receptor and has been used to treat serotonin syndrome with mixed success (anecdotal case reports).
Drug Indications ::
Tocontrol excessive sinus tachycardia or ventricular arrhythmias causedby catecholamine excess (eg, theophylline or caffeine), sympathomimeticdrug intoxication (eg, amphetamines, pseudoephedrine, or cocaine), orexcessive myocardial sensitivity (eg, chloral hydrate, freons, orchlorinated and other hydrocarbons).
Tocontrol hypertension in patients with excessive beta-1–mediatedincreases in heart rate and contractility; used in conjunction with avasodilator (eg, phentolamine) in patients with mixed alpha- andbeta-adrenergic hyperstimulation.
Toraise diastolic blood pressure in patients with hypotension caused byexcessive beta-2–mediated vasodilation (eg, theophylline ormetaproterenol).
Mayameliorate or reduce beta-adrenergic–mediated electrolyte and othermetabolic abnormalities (eg, hypokalemia, hyperglycemia, and lacticacidosis).
E. Serotonin syndrome (see Serotonin syndrome).
Drug Contra-Indications ::
Usewith extreme caution in patients with asthma, congestive heart failure,sinus node dysfunction, or another cardiac conduction disease and inthose receiving calcium antagonists and other cardiac-depressant drugs.
Donot use as a single therapy for hypertension resulting fromsympathomimetic overdose. Propranolol produces peripheral vascular betablockade, which may abolish beta-2–mediated vasodilation and allowunopposed alpha-mediated vasoconstriction, resulting in paradoxicworsening of hypertension; coronary artery constriction may cause orexacerbate acute coronary syndrome.
Drug Adverse Effects ::
IV. Adverse effects
Bradycardia and sinus and atrioventricular block.
Hypotension and congestive heart failure.
Bronchospasm in patients with asthma or bronchospastic chronic obstructive pulmonary disease. Note: Propranolol (in smallintravenous doses) has been used successfully in asthmatic patientsoverdosed on theophylline or beta-2 agonists without precipitatingbronchospasm.
Use in pregnancy. FDAcategory C (indeterminate). Propranolol may cross the placenta, andneonates delivered within 3 days of administration of this drug mayhave persistent beta-adrenergic blockade. However, this does notpreclude its acute, short-term use in a seriously symptomatic patient(see Table III–1).
Drug Lab Interactions ::
Drug or laboratory interactions
Propranololmay allow unopposed alpha-adrenergic stimulation in patients with mixedadrenergic stimulation (eg, epinephrine surge in patients with acutehypoglycemia, pheochromocytoma, or cocaine or amphetamineintoxication), resulting in severe hypertension or end-organ ischemia.
Propranolol has an additive hypotensive effect with other antihypertensive agents.
This drug may potentiate competitive neuromuscular blockers (see Neuromuscular Blockers).
Propranolol has additive depressant effects on cardiac conduction and contractility when given with calcium antagonists.
E. Cimetidine reduces hepatic clearance of propranolol.
F. Propranolol may worsen vasoconstriction caused by ergot alkaloids.
Drug Dose Management ::
Dosage and method of administration
Parenteral. Give0.5–3 mg slow IV not to exceed 1 mg/min (children 0.01–0.1 mg/kg slowIV over 5 minutes; maximum 1 mg/dose) while monitoring heart rate andblood pressure; dose may be repeated as needed after 5–10 minutes. Thedose required for complete beta receptor blockade is about 0.2 mg/kg.For serotonin syndrome, give 1 mg IV not to exceed 1 mg/min (children0.1 mg/kg/dose over 10 min; maximum 1 mg/dose) every 2–5 minutes untila maximum of 5 mg. May repeat at 6- to 8-hour intervals.
Oral. Oraldosing may be initiated after the patient is stabilized; the dosagerange is about 1–5 mg/kg/day in three or four divided doses for bothchildren and adults. For serotonin syndrome, an adult dose of 20 mgevery 8 hours has been used.
Drug Chemical Formulations ::
Parenteral. Propranolol hydrochloride (Inderal and others), 1 mg/mL in 1-mL ampules, vials, and prefilled syringes.
Oral. Propranololhydrochloride (Inderal and others), 60-, 80-, 120-, and 160-mgsustained-release capsules; 10-, 20-, 40-, 60-, 80-, and 90-mg tablets;4-, 8-, and 80-mg/mL oral solution and concentrate.
The suggested minimum stocking level to treat a 70-kg adult for the first 24 hours is 10 ampules or syringes.